Treatment of soya beans



Sept' 2, 1952 I I P. A. SINGER ET AL I y 2,609,299

TREATMENT OF' SOYA BEANS y Filed sept. 27, 1949 Patented Sept. 2, 1952 Ill., assignors to Allie tion of Indiana d. Mills, Inc., a. corpora- Application September 27, 1949, Serial No. 117,957

'Ihis invention relates to the treatment of soy beans Vand more particularly to the preparation of soyybeans for the solvent extraction of oil therefrom. ThisY application is a continuationinepartofour copending application Serial Number 574,674, led January' 26, 1945, now abandoned.

.In-general, methodsnoW used fortheprocessing 'of soy beans involve the steps of cracking, aking, extracting Which are followed by atmos-v pheric distillation of the solvent from the oil and extracted ake. The flakeis then (atmospherically.) toasted'and ground.

The methods commonly used are uneconomical for the mostipart due to ineiiiciencies in processing. In addition the vduality of the iinishedproducts is generally either W or the methods used to improve Vthe quality of the products 4are inefficient and lead to unduly high refining and solvent recovery costs. The present invention presents a new and improved method for the processing of soy-beans forthe extraction of voil and the keconomical treatment of the products of the extraction `to obtain high quality finished products. Y

Certainof the steps usedin this 'process' are especially valuable because they result'` inextracted .akes `which may be employed ina variety of Ways to which flakes produced .in .conventional processesV are not. adapted. .Thus, the marketifor thefextracted akes .is broadened, and flexibility of .operation enhanced.

`-oy beans, asA theyeare 'received byI the proc-'- essor,v t are '-often .contaminated lWith Weed.- seeds, dirt, "grin-straw, bean pods and retc. :Ita-these materials-.arenot carefully removed` the 'lighter materials will interferewith the efficiency 'of -ex traction- =and^cause :a considerable' lowering of the-*quality Aof-the lnished meal. Inaddition;v these materialstakeup space inthe extraction equipment, thereby reducing 'the over-all. capacity of the extraction unit.l Dirt and lgrit .are not only inextractable but :they vvorkl intov the moving portionsof thezapparatus, suchas areem'- ployed in the'milling and flaking loperation and the. distillation equipment, causing excessive Wear-and erosion. VShaker screening and aspirating are both desirable to remove the objectionable contaminants from soy beans.

After thoroughlyecleaning the. vbeans the next step; .-iscracking the.V beans. asan antecedent -to subsequentA dehulling .and .flaking .This 'crackingoperation carried. :outin av series'of -metalcracking rolls,v.aiterfvvhich the cracked beans aradehulled, sized, corrected:` for .moisture .con-f 9-C1aims. (Cl. 99-98) t tent when necessary and then heat temperediad smaller grits passing through.y therolls at, th

The next step is the dehulling .Of the cracked and sized grits. Vl-Iulls are dense cellulosicrmaterials, substantially impervious .tof organicsgi--` Vents and contain only ;7t0 1% of fat'..-'1'Ihese hulls areA not a material source .ofv oilandmay, be regarded as a contaminant-so vfar as .the extraction process is concerned. When thehulls are removed the extraction capacity of -theap paratus is immediately'increased by 6 to v15% depending onthe character of the beans i',orbe

extracted. f .w

The removal of the hulls is carried out'rst by aspiration, ,then by screening the hullson -aishaker screen. Hulls blown from beans-,as the ordinary aspirator, containeenoughebeanpara ticles to bring the fat content toY'Ztov 8%.;Blfl passing the hulls over AaA shaker. screen; howener, these ne particles may be economicallyremovedy producing substantially pure hulls contain-inglese than 1% of oil.\,Thus, .without thefloss-of any oil the extraction capacityisdncreased liby-at least the' extentof the hulls fremoved.y `.The fne oily bean particles aremixed'with theSi'Zed'fg-rits particles, -and those whichA are-:producedare1 classed asn-nes which arecarried alongwith the sized grits andagglemorate with them at .the moisture conditioner, asis true of the, .particles removed from -thehulls Only ay few .grits other than fines can.A passl through va-ten fmesh screen4 There. are many disadvantages in viiiaking'fextra large pieces of-,beans .in ythepresence got. smaller pieces or grits. Thel-arger pieces if.sentthrougl r the V-flaking rolls tendv to spreadr .the. rolls. .atthe instant of Vpassage producing .athickerflakeg from all grits atthe instantrof Contact. th

same. time as larger pieces are `not akedQto' same .degree as .Whenuniformly .size dgrit naked.` Theres-ultis thattheflalies areirlj'g in thickness and in area. Such non-uniform flakes will not extract efficiently because:

(1) The pentration of the solvent through the thicker llakes is delayed or incomplete;

(2) The flakes cannot be packed uniformly in the extraction apparatus, resulting in the channeling of the solvent;

(3) The capacity of the extractor is decreased since the lack of uniformity of the ake interferes with the uniform packing of the flakes, causing loose pockets in the flake mass; and

(4) The larger more dense (thicker) flake tends to protect the smaller flake against efficient solvent action.

The removal of the hulls also aids in obtaining a uniform flake since they too, in conjunction with oversize grits, cause a spreading of the flaking rolls thus producing flakes irregular as to size and thickness.

There are other advantages in hull removal which will become apparent as the subsequent steps of the invention are described.

' The next step is the conditioning of the dehulled and sized grits for flaking, so as to produce flakes having suilicient strength to withstand the extraction process without breaking.

Two factors, moisture content and temperature control, are of primary importance in producing a uniform thin flake of sumciently high tensile strength for proper treatment.

The optimum flake thickness and size varies with dilferent types of extractors, and it is the moisture and temperature conditioning which is the principal factor in assuring that the grits may be rolled to the desired thickness and size Without losing resiliency and other desirable characteristics.

`We prefer to use the Hansa-Muhle, or patery noster type extractor, and accordingly will here describe what we have found to be the desirable moisture and temperature conditions to produce a flake suitable for that extractor. The grits must be conditioned to contain not less than 10.5% and not more than 12% of moisture, and the moisture must be uniformly distributed throughout each grit particle. Ifv the moisture content of the grits is too low, the proper conditions for forming a thin resilient flake are not attained and the cell structure, lacking the proper turgidity, is not sufliciently disintegrated for proper extraction of the oil. On the other hand, if the moisture content is too high, the oil in the flake becomes partially emulsined producing a condition which impedes the extraction of the oil.

`The second factor is temperature control. The exact temperature for heat treatment should be predetermined for each batch of soy beans, since beans of various crop years, varieties and growing conditions have different characteristics in this respect. In general, beans having a high oil content require less temperature for flaking than those of low oil content. The temperature is usually held between l5CtV and 175 F.

The moisture content of the grits may be adjusted and a uniform distribution of the moisture is attained, together with the required temperature control, by means of two processing chambers arranged in series. The rst is a tempering chamber where water is added to the grits iflthey are too dry. This chamber is by-passed when the grits have a moisture content above 10.5%. The second chamber is a combination heating and drying unit where the beans are heated to the required temperature and dried to a desired moisture content if this is too high. This chamber is in addition so designed that a stream of air may be passed concurrently over the heated grits to carry olf any excess moisture. The capacities of both of these units are sufficient to allow for complete moisture and temperature equilibrium throughout the mass and also within the grit particles. A mere surface addition of moisture to the cracked beans going to the flaking rolls, which is common practice, is undesirable for the reason that flakes of uniform thickness cannot be produced. The conditioned grits which have been previously cleaned, sized, dehulled and heated are then flaked on conventional cold steel rolls. The chambers and their arrangement are, however, not part of the present invention. The moistening and heating of the beans may be carried out in any suitable fashion.

The clean flakes ready for extraction are of substantially uniform size and thickness because of the dehulling and sizing of the grits prior to flaking, and are of the desired physical characteristics principally due to the moisture and temperature conditioning. As previously pointed out, there are several types of extractors, of both the continuous and batch types, and anyone may be used for extraction provided the flakes have been suitably prepared for the particular type.

In .the Hansa-Muhle, or paternoster type extractor which we prefer, the flakes are loaded into baskets having perforated bottoms, and are and are there leached with the solvent as they are carried on an endless chain inside a gas-tight shell. After the extraction is completed the baskets are dumped into a closed conveyor which removes the flakes from the extraction unit.'

The solvent and extracted materials "miscella are drawn oi at the bottom of the shell. The number of baskets, the size of the baskets and the time of contact with the solvent are all determined by the desired capacity of the extraction unit and by the required eiciency of extraction. To illustrate: if a given plant unit will produce tons of extracted flake of 0.5 to 0.7% of oil per 24 hour period this same plant could produce tons if the allowable oil con' tent of the flake were increased to 1.0 to 1.2%.

If the hulls are allowed to remain with the flakes in the extractor the impervious na-ture of these large coarse hulls interferes with the uniform passage of the solvent through the flakes, causing vthe solvent to channel, or by-pass flakes immediately below the hulls. Thus, the removal of hulls not only increases the overall capacity of the extraction system but in addition increases the efficiency of the solvent extraction as well.

Removal of the hulls, which have a low protein content, also leaves a meal of higher quality by virtue of the elimination of this fibrous poor quality material. Protein content is thus increased and the crude fiber decreased by the extent of the hull removal. For many feed and food uses this higher quality product is very desirable as for food preparations, and poultry and hog feeds.

Hull free material is also advantageous for the production of pure industrial protein preparations. Great advances have recently been made in the extraction of relatively pure soy bean proteins for use as sizes, adhesives, adjuncts to flour and the production of wool-like fibers.` T he de-' hulling `makes possible a more pure raw material enligne der; :the productionefnthese products? havingza higher concentratiorrxof wllroteinby itherssubstan- -tials eliminationcoff arrxinterfering contaminant Hul'ls';areifzparticularlnldetrimentalim .the extraction of pure soy proteins in that theynpartially decomposeifishe .process yielliingssolubl'e' degrad'ationzi products. which` finterferemth thefre- Alco'veryfi and .purnicat'ionfof .the .'"finish'edproduct The solvent is removedffromithe imiscel'la:i lfsolventsplns Jextracti-ves 'at iew-:itemperatures andlinaslfshort atime-a'snpossible. lhe solvent recovery system .is'litherefore foneratedjat. below atmospheric' pressure and l'fthe equipment sis-vso dsignedflthait la vrnminnen:amcuntiof .lmisceuaf isfipr'ocesse At' any'one inl-e. -"This" 'donetfso that-the in siiexposedt'oeaf iniminny of heat treatment efla'sttraces ofisolventiarenremoved Ibyipa'ssin'g v Steam? atredueed' ipressure foverf'fthe on which has been spreadftaf-nlmeby-anyrcf several viaeeepte d1In"ethleds@for extending the eX- po'sedsurfa'ces of oils'l "Apparatus for such process is well known and is not part ofthis invention.

The resulting desolventized oil is'lighter colored :and v' muchv more susceptible :to :refining processes than that Where the solventjisv removed aunder atmospheric pressure. .or even .above .atmospheric pressure as is'sometimes done. eil, free from solventhjstill contains :dissolved impuritiesvsuch'as phosphatides," 'sterols, saponins, gums .and :muci'lagenous materials. These aregsubstantially..removed .by .means of warmiwater or steam 'either continuously. .or in a batcdsystem. 'Ihe .amount `of .water .or steam usedand 'the speed .andextent .of agitation used are determined bythe character of theoil. 1Commer'cial soy beans may vary considerably dni-the nature .of theiroil content. Steamer warmwater is injected into theoil-'iniths process, with violent agitation, and nnally the separation of the coagulated impurities by centrifuging. These impurities so removed may be further processed for the recovery of phosphatides in iiake form according to a method outlined in patent application No. 494,116, now abandoned.

After removal of the bulk of impurities, it is desirable to lter press the oil with diatomaceous earth for clarification and to remove any surplus moisture.

The extracted flake leaving the extractor is, of course, saturated with solvent. In former methods this material was passed through several desolventizingr drums or conveyors, usually two sets of four in series, followed by a deodorizing drum and finally through a toaster, a total of ten units.

By means of the present invention this multiplicity of apparatus may be eliminated. This may be accomplished by circulating superheated vapors, such as those of hexane, repeatedly over and/or through the extracted flakes so that all but the last traces of solvent are removed. The material is next deodorized by blowing steam through the flakes with bleeding olf of the steam to produce a product free from the last traces of solvent and for the removal of constituents which impart a bitter or brany taste to the beans and flakes. The flakes are then either moistened or passed directly to the final treatment, depending upon the use for which the akes are intended. The desolventizing process here described is described in more detail and claimed in co-pending application of Philip A. Singer, Serial Number 20,833, nled April 13, 1948, now abandoned, in favor of a continuation-impart, Ser. No. 225,687 filed May 11, 1951, and the appa- 6. ratusi :forze arryngroutaifthelpmeessis in1.;coperrding'l appli ation` offT the highest' possible nutritional il efficiency. Bleeding oft-of the steamjisfdone'inithis instance togrivd'thepressure vessel ofgeneratedfgas'eisv` ind liberated j air vwhich `-if allowedf'torem nI the vessel A*would causeffaulty'fpressurefread gs .and irregular treatment of the flakes. v '3 TIL however; 'the Efialke is" toI "'beused orthe industrial-1.extraction of proteinjfneatiuentiira tion lis ltolbe 1avoided, The Atreatment isfthenjcarriedA outunder'a vacuum Yand' at-asflow-n tem'- perature as practicable. This low V"temp,eraiture treatment increases -the ,relative"ease"'and'-I degree 'ofprotei-nsolubility. i'

nsome caseshi'gh qualityhull-free flakesmay not be desired as in cattle.,andsheeptfelfid Ifin such "instances, vthe hulls, .after remova1-maybe ladvantageously preground before neincorpnlalg them into menare; :ser cer ein usesgimsdesirable to toastthe'ground "'lrru'lls,,i` in which case,.th'ey arev mixed with Ythe flakes 'b'eforefthe `final v.toasting step .described above. 4Removaloff'hlillsLbefore extraction thus gives 'great 'exibilityin,producin g a wide variety `of "end products. .f'flhus'ffor example, .the extracted nakes .maybe igrcuidgtc meal without reincorporation o-fhulls .topro .nce a 'high-grade. meal; or may. v.be conventedtma cheaper, lower 1duality. ,animal ee'df bygreincor.- porating the ground hulls.

In the drawings a diagrammatic new sheet of the process herein described is set forth purely for the sake of convenience in understanding the operation.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom.

We claim:

1. The method of preparing clean soy beans for solvent extraction of oil which comprises cracking the beans to form grits, separating the hulls from the grits, sorting the grits by size and returning all grits larger than a predetermined size for further cracking, adjusting the moisture content and temperature of the sized grits to permit rolling of the grits into substantially fiat flakes of high tensile strength and resistance to breakage in a solvent extraction process, and then rolling the grits into flakes of substantially uniform size and thickness.

2. The method of claim 1 wherein the grits larger than about one-quarter bean are returned for further cracking.

3. The method of claim 1 which includes the steps of removing all fine oily bean material from the separated hullsand mixing it with the sized grits not later than the moisture adjustment step.

4. The method of preparing clean soy beans for solvent extraction of oil which comprises cracking the beans to form grits of generally uniform size, removing all iine oily bean material from the separated hulls and mixing said material with the grits to form a composite mass, adjusting the moisture content and temperature of the mass to agglomerate the line material with cracking, tempering the sized grits to a moisture content of 10,5% to 12% by weight and a temperature fof 150 to 175 F., and then rolling the grits into. flakes of substantially uniform size and thickness.

6. The method of treating` clean soy beans which comprises cracking the beans to form grits, separating the hulls from thegrits, sorting the grits by size and returning all grits larger than apredetermined size for further cracking, removing all fine oily bean material from the separated hulls and mixing it with the sized grits to form a mass, adjusting the moisture content and temperature of the mass to permit rolling thereof into substantially flat flakes of high tensile strength and resistance to breakage in a solvent extraction process, then rollingv the mass into flakes of substantially uniform size and thickness, and subjecting the flakes to a solvent extraction process.

7. 'I'he .method of treating clean soy beans which comprises cracking the beans to form grits of generally uniform size, separating the hulls from the grits, sorting the grits by size and returning all grits larger than a predetermined sizeL for further cracking, tempering the sized grits to a moisture content of 10.5% to 8 '12%"by weight and a temperature of 150 to 175 F., then rolling the grits into flakes of substantially uniform size and thickness, and subjecting the flakes'to a continuous solvent extraction process.

8, The method of claim 7 wherein all iine oily bean material is removed from'the separated hulls and'mixed with the grits not later than the moisture tempering step.

9. The method of treating clean soy beans which comprises cracking the beans to form grits, separating the hulls from the grits, removing all fine oily bean material from the hulls and mixing it with the grits, adjusting the moisture content and temperature of the grits to permit rolling of theggrits into substantially fiat flakes of high tensile strength and resistance to breakage in a solvent extraction process, and rolling the grits into flakes.

PHILIP A. SINGER. HARO-LD J. DEOBALD.

l REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS y Number Name Date v 1,867,541 Shellabarger J'uly l2, 1932 OTHER REFERENCES Markley: Soybean Chemistry & Tech., page 166, Chem. Pub. C0., 1944.

Satow: Researches on Oil 8a Proteid Extraction From Soy-bean, 1921, pages 17, 22, and 25.

Horvath: Soybean Ind. 1938, pages 54, 56, and 69.

King: Trans. Am. Inst. of Chem. Eng., vol. 40, 1944, pages 533-535 and 542.A 

1. THE METHOD PREPARING CLEAN SOY BEANS FOR SOLVENT EXTRACTION OF OIL WHICH COMPRISES CRACKING THE BEANS TO FORM GRITS, SEPARATING THE HULLS FROM THE GRITS, SORTING THE GRIFTS BY SIZE AND RETURNING ALL GRITS LARGER THAN A PREDETERMINED SIZE FOR FURTHER CRACKING, ADJUSTING THE MOISTURE CONTENT AND TEMPERATURE OF THE SIZED GRITS TO PERMIT ROLLING OF THE GRITS INTO SUBSTANTIALLY FLAT FLAKES OF HIGH TENSILE STRENGTH AND RESISTANCE TO BREAKAGE IN A SOLVENT EXTRACTION PROCESS, AND THEN ROLLING THE GRITS INTO FLAKES OF SUBSTANTIALLY UNIFORM SIZE AND THICKNESS. 